Synthesis of caprolactam from lysine

ABSTRACT

In various embodiments, the present invention can involve a method of synthesizing α-amino-ε-caprolactam. The method can comprise heating a salt of L-lysine in a solvent comprising an alcohol. In other embodiments, the present invention can involve methods for synthesizing ε-caprolactam. The methods can comprise heating a salt of L-lysine in a solvent comprising an alcohol and deaminating the reaction product. In various embodiments, the invention can include methods of converting biomass into nylon 6. The methods can comprise heating L-lysine in a solvent comprising an alcohol to produce α-amino-ε-caprolactam, deaminating to produce ε-caprolactam and polymerizing into nylon 6, wherein the L-lysine is derived from the biomass. In other embodiments, the present invention can include methods of making nylon 6. The methods can comprise synthesizing ε-caprolactam and then polymerizing, wherein the ε-caprolactam is derived from L-lysine.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/635,373, filed on Dec. 7, 2006, now U.S. Pat. No. 7,399,855 whichclaims priority to International Application No. PCT/US2005/020326,filed on Jun. 9, 2005, which claims the benefit of U.S. ProvisionalApplication No. 60/578,620, filed on Jun. 10, 2004, both of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method of synthesizing a caprolactam,and more specifically, synthesizing ε-caprolactam from L-lysine.

BACKGROUND

About 2.5 billion tons of nylon 6 is produced annually on a worldwidebasis. The production of nylon 6 is accomplished by the ring openingpolymerization of the monomer ε-caprolactam. The starting chemicalcompound for the production of ε-caprolactam is benzene which isconverted to either cyclohexane or phenol and either chemical isconverted via cyclohexanone to cyclohexanone oxime and then thisintermediate is heated in sulfuric acid. This chemical reaction is knownas the Beckman rearrangement. The starting chemical benzene is producedvia the refinement of petroleum chemicals.

SUMMARY

The inventors herein have succeeded in devising a new approach in theproduction of ε-caprolactam from natural products. The approach is basedupon the use of L-lysine in a novel process to produce ε-caprolactamwhich is needed as a precursor to nylon 6.

Thus, in various embodiments, the present invention provides a method ofsynthesizing α-amino-ε-caprolactam, comprising heating a salt ofL-lysine in a solvent comprising an alcohol. In various embodiments, themethods comprise heating a salt of L-lysine in a solvent comprising analcohol, and deaminating the reaction product. In various embodiments,the invention includes methods of converting biomass into nylon 6. Suchmethods comprise heating L-lysine in a solvent comprising an alcohol toproduce α-amino-ε-caprolactam, deaminating to produce ε-caprolactam andpolymerizing into nylon 6, wherein the L-lysine is derived from thebiomass.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a block diagram of a process of converting biomass into nylon6.

It should be noted that these figures are intended to exemplify thegeneral characteristics of the invention for the purpose of thedescription of such embodiments herein. These figures may not preciselyreflect the characteristics of any given embodiment and is notnecessarily intended to define or limit specific embodiments within thescope of this invention.

DETAILED DESCRIPTION

The following definitions and non-limiting guidelines must be consideredin reviewing the description of this invention set forth herein. Theheadings (such as “Introduction” and “Summary,”) and sub-headings (suchas “Amplification”) used herein are intended only for generalorganization of topics within the disclosure of the invention, and arenot intended to limit the disclosure of the invention or any aspectthereof. In particular, subject matter disclosed in the “Introduction”may include aspects of technology within the scope of the invention, andmay not constitute a recitation of prior art. Subject matter disclosedin the “Summary” is not an exhaustive or complete disclosure of theentire scope of the invention or any embodiments thereof.

The citation of references herein does not constitute an admission thatthose references are prior art or have any relevance to thepatentability of the invention disclosed herein. Any discussion of thecontent of references cited in the Introduction is intended merely toprovide a general summary of assertions made by the authors of thereferences, and does not constitute an admission as to the accuracy ofthe content of such references. All references cited in the Descriptionsection of this specification are hereby incorporated by reference intheir entirety.

The description and specific examples, while indicating embodiments ofthe invention, are intended for purposes of illustration only and arenot intended to limit the scope of the invention. Moreover, recitationof multiple embodiments having stated features is not intended toexclude other embodiments having additional features, or otherembodiments incorporating different combinations the stated of features.

As used herein, the words “preferred” and “preferably” refer toembodiments of the invention that afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful, and is not intended to exclude other embodiments from the scopeof the invention.

As used herein, the word “include,” and its variants, is intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that may also be useful in the materials,compositions, devices, and methods of this invention.

Caprolactam is primarily used in the manufacture of synthetic fibers,especially nylon 6 that is also used in bristle brushes, textilestiffeners, film coatings, synthetic leather, plastics, plasticizers,vehicles, cross linking for polyurethanes, and in the synthesis oflysine. The starting point for the production of ε-caprolactam isbenzene which is refined from the non-renewable source of petroleum. Inaddition to its limitations due to its source of non-renewablepetroleum, exposure to benzene, which has been linked to acute myeloidleukemia and non-Hodgkin's lymphoma, is a continuing problem for thechemical industry. The most effective way of dealing with benzene'shuman health risk is to eliminate its use. Such a far reaching solutionrequires the elaboration of fundamentally new synthesis for chemicalsderived from benzene. A sugar such as a non-toxic glucose may be a newstarting point for many of these syntheses. In order to use glucose as areplacement for benzene as a starting point for many of these syntheses,a bio-refinery is needed. A bio-refinery is a facility that integratesbiomass conversion processes and equipment to produce fuels, power andchemicals from biomass. The bio-refinery concept is analogous to apetroleum refinery which produces multiple fuels and products frompetroleum. By producing multiple products, a bio-refinery can takeadvantage of the differences in biomass components and intermediates andmaximize the value derived from the biomass feed stock with minimalwaste and emissions. The conversion of biomass into a sugar such asglucose is well known in the art (see Advancing Sustainability ThroughGreen Chemistry and Engineering, ACS Symposium Series, 823, edited byLanky, R. L. and Anastas, P. T., American Chemical Society, Washington,D.C., 2002; Biomass for Energy, Industry and Environment, 6^(th)European Community Conference, edited by Grassi, G., Collina, A. andZibetta, H., Elsevier Science Publishing Co., Inc., New York, 1998;Biobased Industrial Products: Research and Commercialization Priorities,edited by Dale, B. E., Natural Research Council, Washington, D.C., 1999;Emerging Technologies for Materials and Chemicals from Biomass, ASCSymposium 467, edited by Narayan, R., Rowell, R., Schultz, T., AmericanChemical Society, Washington, D.C., 1991).

In the early 1960's, Japanese biotechnology firms discovered a bacterialfermentation technique which started with a sugar and produced lysine.L-lysine is produced and available from many industrial sourcesincluding such companies as Aginomoto, Kyowa Hakko, Sewon, ArthurDaniels Midland, Cheil Jedang, BASF, and Cargill.

The cyclization of L-lysine to form a seven member ring ofα-amino-ε-caprolactam has been attempted before and reports have shownlow yields. Such attempts have included reactions in near super criticalwater (see Japanese Patent No. 2003206276 to Goto et al. issued Jul. 22,2003) or reactions using an excess of Al₂O₃ in toluene (see Blade-Font,A., Tetrahedron Lett., 1980, 21, 2443-2446. Pellegata, R., Pinza, M.:Pifferi G., Synthesis 1978, 614-616).

In one aspect, the invention provides an efficient route for thecyclization for a cyclic amidation reaction to form lactams having ringsizes from 5 to 8 ring members. Following cyclic amidation, otherreactive groups on the cyclic ring may be removed if desired. In oneaspect, the invention provides efficient cyclic amidation carried out inan alcohol solvents having from 2 to 6 carbons. Amino functionalcarboxylic acid useful in the invention improves those that can cyclizeto form a stable lactam, preferably one having from 5 to 8 ring members.The amino functional carboxylic acids can contain other functionalgroups as long as those functional groups do not interfere with theamidation reaction mediated by the 2 to 6 carbon alcohol solvent.

According to the present invention, a new process for the cyclization ofL-lysine to α-amino-ε-caprolactam is described herein. In addition, inaccordance with the present invention, a process for the deamination ofα-amino-ε-caprolactam to ε-caprolactam is described herein. Commerciallyavailable sources of L-lysine such as, but not limited to, L-lysinedihydrochloride, L-lysine hydrochloride, L-lysine phosphate, L-lysinediphosphate, L-lysine acetate, and L-lysine may be used and any neededsteps so that the L-lysine is in the proper state for the followingreactions will be known by one skilled in the art. In addition,commercially available sources of lysine maybe used but a step toseparate the L-lysine from the D-lysine may be added such as, for anexample, a chiral separation step and such separation and purificationtechniques will be known by one skilled in the art. In variousembodiments, a cyclization reaction was initiated after neutralizationof lysine hydrochloride with sodium hydroxide (NaOH). In thisembodiment, the resulting NaCl is precipitated out of the solution andis removed by filtration after the cyclization reaction is completed. Invarious embodiments, water that is generated during the cyclizationreaction may be removed using a Dean-Stark trap. Other methods knownwithin the art may be used to remove the water such as evaporation,crystallization, distillation or any other appropriate method known byone skilled in the art. In various embodiments of the invention, wateris removed as an azeotrope. In various embodiments of the invention, theneutralized L-lysine is heated in an alcohol. In various otherembodiments of the invention, the neutralized L-lysine is heated in thepresence of an alcohol and a catalyst. In some embodiments of theinvention, the alcohol has about 2 to about 6 carbons.

Non-limiting examples of alcohols include 1-propanol, 2-propanol,1-butanol, 2-butanol, isobutanol, 1,2-propanediol, 1,3-propanediol,1,2-butanediol, 1,4-butanediol, all isomers of 5 carbon monols, diolsand triols including with out limitation 1-pentanol, 1,2-pentanediol,1,5-pentanediol, and all isomers of 6 carbon monodiols, diols and triolsincluding without limitation, 1-hexanol, 1,2-hexanediol, 1,6-hexanediol.Other non-limiting examples of 2 to 6 carbon alcohols include glycerol,trimethylolpropane, pentaerythritol and the like. In variousembodiments, the alcohols have a single hydroxyl group. In otherembodiments, the alcohols have 2 hydroxyl groups. In some embodiments,the alcohols have 3 hydroxyl groups. Non-limiting examples of glycolsinclude propylene glycol, butylene glycol, neopentyl glycol and thelike.

In some embodiments of the invention, the catalyst is aluminum oxide(Al₂O₃). In various embodiments of the invention, the heating of theneutralized L-lysine in the alcohol is accomplished by reflux. Invarious embodiments of the invention, the heating of the alcohol and theneutralized lysine in the presence of a catalyst is accomplished byreflux. In various embodiments, the heating is at a high enoughtemperature to allow azeotropic removal of water with the alcohol. Invarious embodiments, the heating is below a temperature that polymerizesthe caprolactam. In some embodiments, the heating is at temperaturesfrom about 99° C. to about 201° C. In a preferred embodiment of theinvention, the alcohol is 1,2-propanediol. In addition to the higheryields by the use of the 1,2-propanediol, this organic alcohol may bereadily available at a bio-refinery since it may be obtained by thehydrogenation of lactic acid which may be readily available as aco-product produced from the biomass. The following are somenon-limiting examples based on reaction (1).

Example 1

A stirred mixture of L-lysine hydrochloride 1 (55 g, 300 mmol) and NaOH(12 g, 300 mmol) in hexanol (1.2 L) is heated to reflux with aDean-Stark trap used to remove H₂O. The suspension is refluxed for 8hours until all starting material is consumed (which maybe determined by1H NMR). The suspension is then cooled and filtered to remove byproductNaCl. The filtrate is concentrated and the resulting crudeα-amino-ε-caprolactam 2 is dissolved in water. After acidification to pH6 with addition of concentrated HCl and partial concentration, crystalsmaybe formed at room temperature to afford α-amino-ε-caprolactamhydrochloride (37 g) in 75% yield.

Example 2

A stirred mixture of L-lysine hydrochloride 1 (55 g, 300 mmol) and NaOH(12 g, 300 mmol) in 1,2-propanediol (1.2 L) is heated to reflux. ADean-Stark trap is used to withdraw the first 120 mL of condensedsolvent. The reaction solution is refluxed for an additional 2 hoursuntil all starting material is consumed (which maybe determined by 1HNMR). The solution is cooled and is concentrated under vacuum. Ethanolis used to completely dissolve the α-amino-ε-caprolactam 2. ByproductNaCl is removed by filtration. The filtrate is concentrated and theresulting crude α-amino-ε-caprolactam 2 is dissolved in water. Afteracidification to pH 6 with addition of concentrated HCl and subsequentpartial concentration, crystals maybe formed at room temperature toafford α-amino-ε-caprolactam hydrochloride (36.5 g) in 74% yield.

Example 3

50 mmols of L-lysine hydrochloride 1 is neutralized with 50 mmols ofNaOH and then 200 ml of ethanol is added. This mixture is heated to 200°C. for eight hours. The yield of α-amino-ε-caprolactam 2 produced bythis reaction is about 47%.

Example 4

30 mmols of L-lysine hydrochloride 1 is neutralized with 30 mmols ofNaOH and then 120 ml of 1-pentanol is added. This mixture is heated to137° C. and is refluxed for 60 hours. The yield of α-amino-ε-caprolactam2 produced by this reaction is about 93%.

Example 5

30 mmols of L-lysine hydrochloride 1 is neutralized with 30 mmols ofNaOH and then 120 ml of 1-hexanol is added. This mixture is heated to157° C. and is refluxed for 8 hours. The yield of α-amino-ε-caprolactam2 produced by this reaction is about 89%.

Example 6

300 mmols of L-lysine hydrochloride 1 is neutralized with 300 mmols ofNaOH and then 1.2 L of 1-hexanol is added. This mixture is heated to150° C. and is refluxed for 8 hours. The yield of α-amino-ε-caprolactam2 produced by this reaction is about 91%.

Example 7

300 mmols of L-lysine hydrochloride 1 is neutralized with 300 mmols ofNaOH and then 1.2 L of 1,2-propanediol is added. This mixture is heatedto 187° C. and is refluxed for 2 hours after removing about the 10% ofthe solvent when the reaction is first brought to reflux. The yield ofα-amino-ε-caprolactam 2 produced by this reaction is about 96%.

Example 8

30 mmols of L-lysine hydrochloride 1 is neutralized with 30 mmols ofNaOH and then 270 mmols of Al₂O₃ is added, followed by the addition of120 ml of 1-butanol. This mixture is heated to 117° C. and is refluxedfor six hours. The yield of α-amino-ε-caprolactam 2 produced by thisreaction is about 92%.

Example 9

30 mmols of L-lysine hydrochloride 1 is neutralized with 30 mmols ofNaOH and then 270 mmols of Al₂O₃ is added, followed by 120 ml of1-pentanol. This mixture is heated to 137° C. and is refluxed for fourhours. The yield of α-amino-ε-caprolactam 2 produced by this reaction isabout 96%.

Methods for deaminating organic compounds are well known in the art.Deamination processes are chosen depending on the reaction conditionsand yield. In various embodiments, deamination may be accomplished byreacting the amino functional intermediate withhydroxylamine-O-sulphonic acid and KOH catalyst. Thehydroxylamine-O-sulphonic acid (NH₂OSO₃H) may be prepared by thereaction of bis(hydroxylammonium sulfate ((NH₂OH)₂H₂SO₄) with fumingsulphuric acid (H₂SO₄—SO₃) (see Matsuguma et al., Inorg. Syn. 1957, 5,122-125). In certain embodiments of the invention, the deaminationreaction is run after the removal of NaCl after the completion of thecyclization reaction as described above. Deamination reactions usinghydroxylamine-O-sulphonic acid have been described before but haveproduced low yields of ε-caprolactam (see Doldouras, G. A., Kollonitsch,J., J. Am. Chem. Soc. 1978, 100, 341-342; Ramamurthy, T. V., Ravi, S.,Viswanathan, K. V. J. Labelled Compd. Rad., 1987, 25, 809-815). Inaccordance with the present invention, the reaction temperature islowered to below the freezing point of water during the addition of thehydroxylamine-O-sulphonic acid. In various embodiments of the invention,the temperature is lowered to about −5° C. and in other embodiments, thetemperature is lowered to about −20° C. In various embodiments, theamine is washed away with a solvent. The solvent may be water or amixture of water and a small organic alcohol. In various embodiments ofthe invention, the solvent is water. The following are non-limitingexamples based on reaction 2 using a product created from Example 7 andproducing similar yields.

Example 10

α-Amino-ε-caprolactam 2 (2.56 g, 20 mmol) is dissolved in 100 mL waterand the solution cooled to −5° C. After addition of KOH (4.48 g, 80mmol) followed by NH2OSO3H (4.52 g, 40 mmol), the reaction solution isstirred at −5° C. for 1 h. The reaction solution is then heated to70-75° C. and is stirred at this temperature for 1 h. The solution isagain cooled to −5° C. followed by addition of more KOH (4.48 g, 80mmol) followed by NH2OSO3H (4.52 g, 40 mmol). After stirring at −5° C.for 1 h, the reaction solution is heated to 70-75° C. and is stirred foranother 1 h. After concentration, the crude product is purified bysublimation to give 1.70 g (75%) of colorless, crystalline ε-caprolactam3.

Example 11

After completion of the cyclization reaction (1) as described above, theNaCl is removed. 20 mmols of α-amino-ε-caprolactam 2 is placed in areaction chamber and the temperature of the chamber is lowered below thefreezing point of water to about −20° C. 800 mmols of KOH is added andthen 400 mmols of hydroxylamine-O-sulphonic acid is added. The amine iswashed away using a solvent that is 240 ml of water and 160 ml ofmethanol. The product, ε-caprolactam 3, is then purified by sublimationand the yield is about 61% based on L-lysine starting material.

Example 12

After completion of the cyclization reaction (1) as described above, theNaCl is removed. 20 mmols of α-amino-ε-caprolactam 2 is placed in areaction chamber and the temperature of the chamber is lowered below thefreezing point of water to about −20° C. 800 mmols of KOH is added andthen 400 mmols of hydroxylamine-O-sulphonic acid is added. The amine iswashed away using a solvent that is 20 ml of water and 80 ml ofmethanol. The product, ε-caprolactam 3, is then purified by sublimationand the yield is about 62% based on L-lysine starting material.

Example 13

After completion of the cyclization reaction (1) as described above, theNaCl is removed. 20 mmols of α-amino-ε-caprolactam is placed in areaction chamber and the temperature of the chamber is lowered below thefreezing point of water to about −20° C. 800 mmols of KOH is added andthen 400 mmols of hydroxylamine-O-sulphonic acid is added. The amine iswashed away using a solvent that is 60 ml of water and 40 ml ofmethanol. The product, ε-caprolactam 3, is then purified by sublimationand the yield is about 64% based on L-lysine starting material.

Example 14

After completion of the cyclization reaction (1) as described above, theNaCl is removed. 20 mmols of α-amino-ε-caprolactam 2 is placed in areaction chamber and the temperature of the chamber is lowered below thefreezing point of water to about −20° C. 160 mmols of KOH is added andthen 80 mmols of hydroxylamine-O-sulphonic acid is added. The amine iswashed away using a solvent that is 60 ml of water and 40 ml ofmethanol. The product, ε-caprolactam 3, is then purified by sublimationand the yield is about 65% based on L-lysine starting material.

Example 15

After completion of the cyclization reaction (1) as described above, theNaCl is removed. 20 mmols of α-amino-ε-caprolactam 2 is placed in areaction chamber and the temperature of the chamber is lowered below thefreezing point of water to about −20° C. 160 mmols of KOH is added andthen 80 mmols of hydroxylamine-O-sulphonic acid is added. The amine iswashed away using a solvent that is 60 ml of water and 40 ml of ethanol.The product, ε-caprolactam 3, is then purified by sublimation and theyield is about 70% based on L-lysine starting material.

Example 16

After completion of the cyclization reaction (1) as described above, theNaCl is removed. 20 mmols of α-amino-ε-caprolactam 2 is placed in areaction chamber and the temperature of the chamber is lowered below thefreezing point of water to about −5° C. 160 mmols of KOH is added andthen 80 mmols of hydroxylamine-O-sulphonic acid is added. The amine iswashed away using a solvent that is 100 ml of water. The product,ε-caprolactam 3, is then purified by sublimation and the yield is about75% based on L-lysine starting material.

Referring to FIG. 1, a process of the present invention is illustratedby a block diagram showing biomass being converted into nylon 6.Biomass, as described earlier, which is a material produced by thegrowth of microorganisms, plants or animals, is supplied to the system.Examples of a biomass include agricultural products and by-products suchas corn, husks, stalks, cereal crops, alfalfa, clover, grass clippings,vegetable residues, straw, maize, grain, grape, hemp, sugar cane, flax,and potatoes; forestry and paper products and by-products such assawdust paper, cellulose, wood pulp, wood chips, pulp sludge and leaves,and other appropriate materials that are known in the art. In variousembodiments of the invention, the biomass is high cellulose-containingmaterials. In other embodiments of the invention, the biomass is highstarch-containing materials. In alternative embodiments, the biomassgoes through fractionization which yields such components as cellulose,hemicellulose, lignocellulose, plant oil, and/or starch as representedby step A. In various embodiments, the box labeled “Cellulose and/orStarch” may comprise but is not limited to starch, cellulose,hemicellulose, lignocellulose, or combinations thereof and the like.Such separation or fractionization of biomass into cellulose componentsand/or starch is well known in the art (see U.S. Pat. No. 6,022,419 toTorget et al. issued Feb. 8, 2000; U.S. Pat. No. 5,047,332 to Chahalissued Sep. 10, 1991 and U.S. Pat. No. 6,228,177 to Torget issued May 8,2001, U.S. Pat. No. 6,620,292 to Wingerson issued Sep. 16, 2003, and B.Kamm and M. Kamm, Biorefinery-Systems, Chem. Biochem. Eng. Q. 18 (1) 1-62004). In various embodiments of the invention, the biomass goes throughstep A can result in a combination of both cellulose components andstarch. In various embodiments of the invention, the biomass is notseparated but, rather, the biomass moves directly to step B. In step Bof FIG. 1, cellulose components, starch, or combinations thereof areconverted to a sugar such as glucose by hydrolyzsis. In variousembodiments, the box labeled “Sugar” may comprise but is not limited toglucose, dextrose, xylose, sucrose, fructose, arabinose, glyercerol,other sugars or polyols known to one skilled in the art or combinationsthereof and the like. In various embodiments of the invention, the rawbiomass is converted to a sugar by hydrolization. In various embodimentsof the invention, the hydrolyzation is an acid hydrolyzation. In otherembodiments of the invention, the hydrolyzation is enzymatichydrolization. Hydrolyzation methods that could produce a sugar such asglucose are well known in the art (see U.S. Pat. No. 6,692,578 toSchmidt et al. issued Feb. 17, 2004, U.S. Pat. No. 5,868,851 to Lightnerissued Feb. 9, 1999, U.S. Pat. No. 5,628,830 to Brink issued May 13,1997, U.S. Pat. No. 4,752,579 to Arena et al. issued Jun. 21, 1988, U.S.Pat. No. 4,787,939 to Barker et al. issued Nov. 29, 1988, U.S. Pat. No.5,221,357 to Brink issued Jun. 22, 1993 and U.S. Pat. No. 4,615,742 toWright issued Oct. 7, 1986). Depolymerization of hemicellulose producesD-xylose and L-arabinose, which can serve as alternative startingmaterials for microbial synthesis of chemicals. Plant oils are anothercomponent of biomass. Transesterification of plant oils leads toesterified fatty acids which maybe used as biodiesel and glycerol, whichis another polyol suitable for use as a starting material in microbialsynthesis. In various embodiments of the invention, step B may produceother sugars that may or may not include glucose.

Since the early 1960's, Japanese companies have been perfectingfermentation of L-lysine produced from sugars such as glucose. Unlikehuman beings and animals, the Corynebacterium glutamicum bacterium isable to synthesize lysine. Through classical strain optimization, thebacteria have become able to synthesize large quantities of lysine.Production takes place in fermenters in which the Corynebacteriumglutamicum bacterium converts raw sugars such as glucose, sugar cane,and/or molasses into lysine. Such processes are well known in the art(see U.S. Pat. No. 2,979,439 to Kinoshita et al. issued Apr. 11, 1961,U.S. Pat. No. 3,687,810 to Kurihara et al. issued Aug. 29, 1972, U.S.Pat. No. 3,707,441 to Shiio et al. issued Dec. 26, 1972, U.S. Pat. No.3,871,960 to Kubota et al. issued Mar. 18, 1975, U.S. Pat. No. 4,275,157issued to Tosaka et al. issued Jun. 23, 1981, U.S. Pat. No. 4,601,829issued to Kaneko issued Jul. 22, 1986, U.S. Pat. No. 4,623,623 issued toNakanishi et al. issued Nov. 18, 1986, U.S. Pat. No. 4,411,997 issued toShimazaki et al. issued Oct. 25, 1983, U.S. Pat. No. 4,954,441 issued toKatsumata et al. issued Sep. 4, 1990, U.S. Pat. No. 5,650,304 issued toIshii et al. issued Jul. 22, 1997, U.S. Pat. No. 5,250,423 issued toMurakami et al. issued Oct. 5, 1993, U.S. Pat. No. 4,861,722 issued toSano et al. issued Aug. 29, 1989, and Manufacturing of Stabilised BrownJuice for L-lysine Production—from University Lab Scale over Pilot Scaleto Industrial Production, M. H. Thomsen et al., Chem. Biochem. Eng. Q.18 (1) 37-46 (2004).

L-lysine hydrochloride is produced by the treatment of L-lysinesolutions with 10% hydrochloric acid to adjust the pH to about 4.5 toabout 4.7. It is then heated with activated charcoal at about 80° C. forabout 40 minutes to eliminate the color then filtered. The clearfiltrate is evaporated under vacuum at about 40° C., cooled and allowedto stand at about 4° C. for about 24 to about 36 hours. The precipitatedcrystalline L-lysine monochloric acid is separated by filtration andpurified by repeated crystallization from ethanol.

Step D is the cyclization of the L-lysine hydrochloric acid toα-amino-ε-caprolactam as described in the present invention from above.Such examples as 1-9 herein and any modifications that would be apparentto one skilled in the art are conditions and reactions for step D. Invarious embodiments, L-lysine is not converted to L-lysinehydrochloride. In such embodiments, the neutralization step may beomitted from step D. Step E is the deaminization ofα-amino-ε-caprolactam to ε-caprolactam as described herein. Examples10-16 and any modifications that would be apparent to one skilled in theart are reactions that may be used in step E.

The polymerization of ε-caprolactam to nylon 6 is step F and thisreaction was invented by Paul Schlack of IG Farben in Germany on aboutJan. 28, 1938. The reaction is a ring opening polymerization from themonomer ε-caprolactam which is accomplished by heating the ε-caprolactamto about 250° C. with about 0.3% to about 10% water present. See U.S.Pat. No. 2,142,007 to Schlack issued Dec. 27, 1938 and U.S. Pat. No.2,241,321 to Schlack issued May 6, 1941. The polymerization ofε-caprolactam to nylon 6 is well known in the art. A non-limitingexample of such polymerization is as follows: nylon 6 may be produced byhydrolytic polymerization of caprolactam, with predominant use of the VKtube (abbreviation for the German expression “vereinfachtKontinuierlich” which means simplified continuous) a heated verticalflow pipe. The molten caprolactam, with 0.3-5% of water, chain lengthregulators, and, if necessary, a dulling agent, is fed from above, andthe polymer melt is discharged at the reactor bottom. Typically the VKtube is equipped with 3 heat exchangers establishing the temperatureprofile along the reactor. The VK-tube consists of a plug flow zone inthe lower part and a mixing/evaporating zone in the top. The function ofthe top part is to heat up the reaction mass and to evaporate excesswater thus setting the total water content in the polymer melt. Theendothermic caprolactam ring opening reaction is started, followed byexothermal polyaddition and polycondensation. With the central heatexchanger, the temperature is corrected and equalized over the tubecross section. After passing the central heat exchanger, the temperaturerises to about 270-280° C. due to the heat of reaction. The bottom heatexchanger drops the temperature to 240-250° C., thus reaching a higherdegree of polymerization in the equilibrium. Simultaneously a higherdegree of caprolactam conversion to nylon 6 is achieved. Specificallydesigned inserts are applied evening out the dwell time over the tubecross section. Sixteen to twenty hours may be the mean dwell time in thetube. Relative solution viscosities from 2.4 to 2.8 are achieved with asingle stage process (solvent: 96% sulphuric acid, concentration: 1g/100 ml, temperature: 25° C.). The maximum capacity may be 130tonnes/day. In the 2-stage technology, a prepolymerizer, operated underpressure and with high water content, is followed by a final VKpolymerizer operated at atmospheric pressure or vacuum. The highreaction rate of the caprolactam ring opening under the conditions inthe prepolymerizer yields a low total residence time making the processsuitable for very high throughput rates up to 300 tonnes/day.

In various embodiments of the process as described in FIG. 1, additionsmay be made such that the amine that is a by-product from step E may berecycled so that the nitrogen may be added in step C as a nutrient forfermentation. In other embodiments, the amine that is a by-product instep E may be recycled so that the nitrogen may be added in step B as anutrient for fermentation. In an alternative embodiment, one skilled inthe art may precipitate the monophosphate or diphosphate salt of lysine.The sodium phosphate salt (monobasic or dibasic) generated duringcyclization of lysine phosphate maybe (like ammonia above) from step Emay be recycled so that the phosphorus may be added in step C as anutrient for fermentation.

In various embodiments of the invention, a portion of the biomass may beconverted into lactic acid and then hydrogenated into 1,2-propanediolwhich maybe used in Step D. The process of taking biomass and convertingit into lactic acid is well known in the art. (See U.S. Pat. No.6,403,844 to Zhang et al. issued Jun. 11, 2002, U.S. Pat. No. 4,963,486to Hang issued Oct. 16, 1990, U.S. Pat. No. 5,177,009 issued Kampenissued Jan. 5, 1993, U.S. Pat. No. 6,610,530 issued to Blank et al.issued Aug. 26, 2003, U.S. Pat. No. 5,798,237 issued to Picataggio etal. issued Aug. 25, 1998, and U.S. Pat. No. 4,617,090 to Chum et al.issued Oct. 14, 1986, Zhang, Z; Jackson, J. E.; Miller, D. J. Appl.Catal. A-Gen. 2001, 219, 89-98, Zhang, Z; Jackson, J. E.; Miller, Ind.Eng. Chem. Res. 2002, 41, 691-696).

The examples and other embodiments described herein are exemplary andare not intended to be limiting in describing the full scope ofapparatus, systems, compositions, materials, and methods of thisinvention. Equivalent changes, modifications, variations in specificembodiments, apparatus, systems, compositions, materials and methods maybe made within the scope of the present invention with substantiallysimilar results. Such changes, modifications or variations are not to beregarded as a departure from the spirit and scope of the invention. Allpatents cited herein, as well as, all publications, articles, brochuresand product information discussed herein, are incorporated in theirentirety herein by reference.

1. A method for producing nylon 6, the method comprising: (A) heatinglysine in a solvent comprising an alcohol, at a temperature of about 99°C. to about 201° C., to produce α-amino-ε-caprolactam; (B) deaminatingα-amino-ε-caprolactam produced in (A) by a method comprising contactingit at least once with a deamination reagent or catalyst at a temperaturebelow the freezing point of water, to produce ε-caprolactam; and (C)polymerizing ε-caprolactam produced in (B) into nylon
 6. 2. A methodaccording to claim 1, wherein the lysine comprises L-lysine derived frombiomass.
 3. A method according to claim 2, wherein the L-lysine isderived by obtaining a sugar from the biomass and converting the sugarinto L-lysine.
 4. A method according to claim 3, wherein the convertingcomprises using a fermentation reaction to convert the sugar intoL-lysine.
 5. A method according to claim 4 further comprising recyclingan amine, produced by deamination of α-amino-ε-caprolactam, into thefermentation reaction.
 6. A method according to claim 2 furthercomprising creating lactic acid from the biomass.
 7. A method accordingto claim 6 further comprising hydrogenating the lactic acid to produce1,2-propanediol.
 8. A method according to claim 7 further comprisingusing the 1,2-propanediol as the alcohol in the heating step (A).
 9. Amethod according to claim 1, wherein the heating (A) comprises heatingin the presence of a catalyst.
 10. A method according to claim 1,wherein the alcohol used in the heating step (A) has from 2 to 6carbons.
 11. A method according to claim 10, wherein the alcoholcomprises a diol.
 12. A method according to claim 10, wherein thealcohol comprises a triol.
 13. A method according to claim 10, whereinthe alcohol comprises a glycol.
 14. A method according to claim 10,wherein the alcohol is from the group consisting of ethanol, 1-propanol,1-butanol, 1-pentanol, 1-hexanol, 1,2-propanediol, and mixtures thereof.15. A method according to claim 14, wherein the alcohol is1,2-propanediol.
 16. A method according to claim 1, wherein the heatingis below the temperature of polymerization of caprolactam.
 17. A methodaccording to claim 1, wherein the heating allows the azeotropic removalof water.
 18. A method according to claim 1, wherein the heating isaccomplished by reflux.